facebook issue

Yes, go into her profile by typing her name in your search bar, then tap/click where it says friend.

Yes

go here

www.facebook.com/help/172936839431357

if you cannot do this yourself, find a trustworthy person to help.

You can also temporarily close your account for a period - you need to google how and maybe get help, to do that

or decide to leave Facebook altogether and keep in contact with those you do trust via WhatsApp

Did you accept a friend request from her? I’d have just ignored it and erred on the side of caution.

Cancel her as described above and don’t do FB for a while.

I hope it all blows over soon.

I’d go with Wyllow’s advice.
Under the circumstances, FB might not be the best place for you.

She didn’t really have to hunt you down if you liked her post not did you have to accept her friendship request. How is it that you know so much about her?

Others have explained how to unfriend her.

If you want to stay on FB you can change your name. Once you have done that, make sure your privacy settings are what you want them to be so that only people you trust can see you.

It would take too long to explain how to do this but if you search on “How can I stop anyone seeing my Facebook activity” it will take you to instructions.

I assume she doesn’t know where you live and could compromise your physical security.

Click your profile picture in the top right of Facebook.
Select Settings & privacy, then click Settings.
In the menu, click Blocking under Audience and visibility.
In the Block profiles and Pages section, click Edit.
Click Add to blocked list.
Type the name of the profile or Page you want to block.
Click Block next to their name.
Click Confirm.